Starting Point
A plant vented 2 MW of exhaust at 320 degrees C, twenty-four hours a day. The goal was power with the shortest payback.
Survey and Choice
- Heat profile was steady, so an ORC beat a steam plant on cost and speed.
- A siloxane fluid was chosen for the high temperature, matched to an Incoloy evaporator.
- An isolated plate air-to-air preheater recovered part of the heat to cut fuel before the ORC loop.
Outcome
The ORC delivered about 180 kW of continuous power. Air preheat cut fuel by a further 8 percent. Combined savings paid the system back in under five years, and the isolated exchanger kept maintenance simple on the dirty exhaust stream.